Lighting and illumination is becoming increasingly sophisticated in order to allow consumers to take advantage of the recent advancements in areas such as solid state lighting and flat panel display technology. For example, there is, for various applications a drive towards achieving thin, large area illumination devices or luminaires having advantageous illumination properties. For that purpose, as well as for numerous other applications, there is a need for the ability to accurately control the direction of light in a compact structure, and to achieve this in an inexpensive manner.
One approach for controlling the direction of light in such a structure is disclosed in US 2003/0095332, in which an optical element for use in a display apparatus is described. This optical element is formed by a light directing film, which has one surface with saw-tooth formations. This surface is provided with a metal coating which is protected by a polymer protective layer. The metal coating forms an internal reflector in the light directing construction.
This reflector, however, is prone to being damaged though corrosion and is typically formed in an inherently expensive vacuum process.